[Stratos-dev] Configuring the host GIC for guest to guest IPI

Hi GIC experts,

This came up last week in the Stratos sync call when we were discussing Vincent's SCMI setup:

https://linaro.atlassian.net/wiki/spaces/STR/pages/28665741503/2021-12-09+Pr...

with the shared memory between the two guests the only reason we currently exit to the guest userspace (QEMU) is to forward notifications of virtqueue kicks from one guest to the other. I'm vaguely aware from my time looking at GIC code that it can be configured for IPI IRQs between two cores. Do we have that ability between two vCPUs from different guests?

If not what would it take to enable such a feature?